Metasonix F-1

Metasonix F-1 Complex Distortion Pedal
Ever wondered what would happen if you deliberately destroyed your tube amp? Now you can blow it up, every day, all day long. Without actually damaging anything.
The F-1 pedal uses a unique vacuum-tube pentode circuit to do something special: it simulates the extreme distortion, parasitic oscillations, and other unique sounds that come from a tube guitar amp that is being overdriven to flaming destruction.
There's only one knob to adjust, and it only needs one knob.
“Complex Distortion” varies the plate loading on the two pentodes to give asymmetrical distortion, and it varies the feedback effects—all on one knob. Typical of the things that happen when the EL34s in a Marshall or similar amplifier are driven to the point of meltdown, and the power and output transformers threaten to go open-circuit. You can almost smell the smoke pouring out.
A vast cornucopia of sound effects, from mild vacuum-tube warmth to berserk torturous screaming violence, is just a knob-turn away.
It's hand-made, in California, by real people. It uses real new-old-stock American vacuum tubes (replacements are quite easy to obtain). And there's nothing else even vaguely like the F-1, in any form.